In the Balmer series,the wavelength of the $2^{\text{nd}}$ line is $\lambda_1$ and for the Paschen series,the wavelength of the $1^{\text{st}}$ line is $\lambda_2$. Then the ratio $\lambda_1 : \lambda_2$ is:

The maximum number of emission lines for atomic hydrogen that you would expect to see with the naked eye if the only electronic levels involved are those shown in the figure,is

The Lyman series of the hydrogen spectrum lies in which region?

In the hydrogen atom spectrum, ($R$ is Rydberg's constant):
$A$. The maximum wavelength of the radiation of the Lyman series is $\frac{4}{3R}$.
$B$. The Balmer series lies in the visible region of the spectrum.
$C$. The minimum wavelength of the radiation of the Paschen series is $\frac{9}{R}$.
$D$. The minimum wavelength of the Lyman series is $\frac{5}{4R}$.
Choose the correct answer from the options given below:

The difference between the frequencies of the second and first Paschen lines of the hydrogen atom is (where $R$ is the Rydberg constant and $c$ is the speed of light in vacuum).

The first member of the Paschen series in the hydrogen spectrum has a wavelength of $18,800 \,\mathring{A}$. The short wavelength limit of the Paschen series is ...... $\mathring{A}$.